Helical Gears Number of Teeth : 18 Model Number : Timing Pulley 5M18T Material : Alloy Type : Timing Teeth pitch: : 5 mm Pulley shape: : BF shape Inner bore: : 6/6.35/8/10/12/14 mm Slot width: : 16/21/27 mm Belt width: : 15/20/25 mm